1. Field
Example embodiments relate to a cell balancing circuit and a secondary battery with the cell balancing circuit, and more particularly, to a cell balancing circuit with a self-balancing function and a secondary battery with the cell balancing circuit.
2. Description of the Related Art
Recently, the use of portable electronic devices is increasing with the rapid development of the electronic, communication and computer industries. Rechargeable secondary batteries are being widely used as power sources for portable electronic devices.
A secondary battery with a plurality of serially-connected unit cells is used for a high power source. Cell balancing is important when using a secondary battery with a plurality of serially-connected unit cells. The cell balancing is to maintain the voltage difference between the serially-connected unit cells to be within an allowable range. The cell balancing greatly influences the lifetime and output power of the secondary battery. If failing to be cell-balanced, the unit cell degrades, thus reducing the lifetime and output power of the secondary battery.
In a related art cell balancing method, a control IC compares the voltage of each unit cell with a reference voltage and discharges the unit cell exceeding the reference voltage, through a discharge path formed corresponding to each unit cell.